Currently, next generation standards (5G or a new radio access technology (NR)) of a long term evolution (LTE) system and an LTE-advanced system are under review in third generation partnership project (3GPP). As one of discussions in 3GPP, communication states of user equipments (UE) are under review. In the LTE system and the LTE-advanced system, it is specified that user equipments operate in two communication states, that is, a connected state by RRC_Connected and an idle state by RRC_Idle in radio resource control (RRC) that control radio networks.